


the spell

by WattStalf



Series: Commissions [419]
Category: Fire Emblem Series, Fire Emblem: If | Fire Emblem: Fates
Genre: Blow Jobs, Dubious Consent, F/M, Mindbreak, Other Additional Tags to Be Added, Vaginal Fingering, Vaginal Sex, commission
Language: English
Status: In-Progress
Published: 2021-03-13
Updated: 2021-03-13
Packaged: 2021-03-21 09:34:10
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 3,023
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/30019731
Author URL: https://archiveofourown.org/users/WattStalf/pseuds/WattStalf
Summary: Elise finds a spell that she hopes will help Corrin. It definitely helps him, by way of turning her into his mindbroken sex slave, but Corrin is quick to realize that might be so bad. And Elise isn't the only one...
Relationships: Elise/My Unit | Kamui | Corrin
Series: Commissions [419]
Series URL: https://archiveofourown.org/series/1325462
Kudos: 6





	the spell

Elise knows that her big brother has been under a lot of stress lately, what with all of the new information he has been forced to take in about himself. Despite finding out that they are not blood related, he still remains as close to her as ever before, but the fact that he will have to go to war with his Hoshidan family is weighing heavy on his mind, and that is not even including the recent revelation of his apparent ability to transform into a dragon.

All of this is weighing heavily on him, and Elise just wants a way to help her big brother out. That is why she wants to research magic that might ease his stress, but when she tries to talk to Leo about it, he tells her that there is no such thing, and that she should not expect magic to solve every problem. Camilla is too busy to offer her any advice either, and so, she decides that it is all up to her.

Fortunately for her, there are plenty of magic books at her disposal. Unfortunately, most of them do not seem to have what she is looking for, until finally, she has to start looking in new places. Sneaking into Iago’s personal library is no easy feat, but she manages, and even manages to find the type of book that she is looking for, with a spell that she thinks will work perfectly to help Corrin, bringing it to him as soon as possible.

“Elise, you didn’t have to do this for me,” he tries to assure her, but she will hear none of that. In her mind, this is her duty as his little sister, and she is determined to perform the magic, all so that she can make her big brother feel better. Corrin decides to let her try it out, since it seems to mean so much to her, and since she wants so badly to make him feel better.

The spell does not work as planned, though. Neither is sure where it went wrong, or where _they_ went wrong in assuming its meaning, but both know immediately that things are not working as they are supposed to. Corrin not only feels the same, but also does not feel any magic taking hold of him. At the same time, Elise can tell that the spell, though aimed for her brother, has entirely taken hold of her. That is the last clear thought she has, before her mind begins to cloud over, until finally, there is only one thought left in it.

“Let me take care of you,” she says, and Corrin has no idea what to make of that.

“What do you mean? Because the spell hasn’t done anything yet?” he asks. “It’s alright, Elise, you don’t have to worry about anything. I’m sure that I’ll be just fine-”

“I’m here to serve you, big brother,” she interrupts, moving closer to him, and there is something different about the look in her eyes. What neither of them realize is the spell is a lot more specific than either of them knew, and they were playing with something very dangerous, something that could channel the deepest desires of the target. Elise had no way of knowing the level of lust Corrin kept inside, and neither could know that the spell would channel it quickly.

So, rather than changing Corrin, it has changed Elise. Just like that, the Elise that he knew is lost to him forever, replaced by his personal sex slave, eager to please him and serve him, all as a means of relieving his stress. Corrin has no idea how to react to this, but as she drops to her knees in front of him, his body starts to react all on its own, and he just goes along with what his body wants, even though there is a part of his mind telling him that this isn’t normal, that it isn’t right, that this isn’t Elise.

Once she has his cock out and in her hand, there is nothing he can do but give into his desire. He has never wanted something as badly as this, and even if he does not understand it, he can’t just resist it. Elise wraps her lips around the tip of his cock, and he never thought he would ever be able to use his own little sister like this. Even if he is not actually blood related to this family, that does not change the years they spent together, and so, she is still his little sister.

She is his little sister, and he wants her so bad it hurts, has always wanted her, and he just never allowed himself to think about it, always trying to deny it. Now, she is right here on her knees, claiming that she wants to serve him, and all he can do is clap a hand on the back of her head, pushing her as far forward as he can, letting her gag on his cock. It is as if he is compelled to test her, and to see if she really means it when she says that she will serve him, to test her limits and see just how far she is willing to go for him.

“If you really want to take care of me, then just let me do whatever I want to you, alright, Elise?” he asks her. He halfway expects her to try and resist him, to try and pull away as she is left choking on his cock, but instead, she looks up at him, her eyes watered a bit, but there is nothing but adoration in her gaze.

At this point, it no longer matters to him what has happened to her, and it no longer matters that she no longer resembles his little sister anymore. Elise has become everything he has ever wanted, all in the blink of an eye, and Corrin is going to take advantage of that.

Before long, Corrin has completely lost himself in the motions of fucking Elise’s face, holding her steady as he thrusts forward, groaning and showing her no mercy. He has spent so long resisting his feelings for her; every time that she has come to visit him, every time that they have been left alone together, he has had to resist how much he wants her, trying to keep his hands to himself, trying to remind himself that he should not lust for his little sister like this, but nothing has ever managed to completely rid him of those feelings.

And now those feelings have come back to haunt him, in the best way possible. Now, Elise is completely broken for him, because the spell that she chose targeted his deepest desires, and those desires just happened to involve her. He has no idea how much of her is really left in there, or if she understands that, by trying to help her big brother so much, she has given herself away to him like this.

Would she be happy about this outcome either way? There is no way for him to find out, so he just has to embrace the fact that she is happy about it right now, because this is the only Elise that he has left. This is the Elise that lets him fuck her face and beams up at him all the while, barely even seeming to notice that she is left choking on his cock, as he does not even attempt to be gentle with her. It all comes to him so easily, so naturally, when she is so willing to submit without a hint of a fight.

“You’re doing such a good job, Elise,” he groans, praising her as best as he can right now. “I’m so proud of you, you’re such a big help…” There really aren’t words to express just how much she has done for him, but he will show her in actions, as he continues to take advantage of her new, vulnerable state, and just how much she loves every second spent as his personal sex slave.

Jerking his hips forward with even more force, he knows that it will not be long before he is pushed over the edge, and he decides to give her no option in that regard. She is his now, to do whatever he wants with, so swallowing his load should be no trouble for her. In fact, if she is as happy to serve as she acts, then she should enjoy it, she should love having him come right down her pretty little throat.

“Here you go, Elise, I…ah!” With a sharp moan, he hilts himself inside of her mouth, holding her still as he lets go, coming hard and filling her throat with it. Elise is happy to swallow it, just like he assumed she would be, beaming all the while. No matter what he does to her, she is going to love it, because from now on, she lives only to serve his needs.

That is not nearly enough to satisfy him, not after years of keeping this lust to himself and letting it build up, and not when she has awoken this appetite in him. His stamina might even be helped out by his recently discovered draconic abilities, making it easier for him to bounce right back, already hard again by the time he has pulled out of Elise’s mouth. Looking down at her on her knees, he has one simple order for her.

“Strip.”

Elise moves quickly, taking her clothes off for him with ease. Of course, she is used to a complicated outfit like that, whereas he would have struggled to figure out how to get it off of her, and in no time at all, she is completely naked in front of him, letting him take in every detail of her naked body. She is even more perfect than he could have imagined, and he can hardly contain himself, just looking at her like this. He knows that he has to have her, that he has to have her over and over again, making her his in every way imaginable.

“Let’s see if you’re ready,” he says, moving closer to her so that he can touch between her legs. Even though he knows that she will not complain, that she will endure anything as long as it is for him, at least if the spell is as complete as it seems, he still wants to try and make her first time as pleasant as he can. This is something he has often fantasized about sharing with Elise, and he wants her to be ready for it, wants her to love it.

That being said, as soon as he touches her, he can feel just how dripping wet she already is. Not only has the spell made her think she likes everything he does to him, it has influenced her body’s reactions as well, with Elise genuinely turned on by all of this. Of course, he has no way of knowing if she would have gotten this turned on either way, but there is a part of him that now wonders if she might have felt at least a little bit of lust towards him, before the spell took hold. It is probably just that potent, but it makes it seem like it is working with something that was already there.

As he fingers her, she moans out for him, going to pieces from even the slightest touch. “Please, please fuck me,” Elise begs him, her voice quivering in her excitement. “I want you to fuck me, so you can use my body as much as you need to!”

“Don’t you worry about that, Elise. I’m going to fuck you over and over again, until I’m completely worn out,” he promises her, and that promise seems to thrill her to her very core, making her shudder for him. With that, he turns her around and bends her over so that he can make good on that promise, deciding not to keep teasing things out just to make sure that she is ready. If she is begging him like this, then clearly she wants it, and who is he to deny his adorable, needy little sister?

Gripping tight to her hips, he pushes the tip of his cock up against her, so caught up in it all that he hardly even remembers his initial reluctance to take things so far, or the implications of the spell that has been cast. Somewhere in the back of his mind, he must still wonder what will happen if she never returns to normal, but at this point, he wants her so badly that he does not care, and this is definitely something that he will be able to get used to.

With a rough thrust, he buries himself inside of her all at once, hilting his cock in her and making her scream out. That may have been too much for her first time, even with how much she wanted it, even with how wet she was, but he is past the point of being able to hold that back, especially after being begged to fuck her. Either way, she is in no state to tell him if it was too much or not, not even able to register something like that for herself, and so, she gives into him immediately, her scream fading into a moan as Corrin, once completely inside of her, goes still to regain his composure.

She is so warm and tight around him, and it all feels so good that he can hardly stand it. After already having his way with her mouth, it almost feels too good to be true, and this feels so much better that he wonders if such a thing is even possible. He has to remain still for a bit, just to make sure that he is able to handle this, and that he does not take things so far that he loses himself completely, right out of the gate. Corrin wants to make this last, wants to enjoy this as much as he possibly can.

That being said, he has a feeling that they are going to be at this for a while, considering his promise to fuck her until he has worn himself out.

Finally confident in his ability to keep going, he begins thrusting into her, starting out with a slow pace, testing the waters, but he is so quickly swept away in how it feels, fucking something so tight, that he can’t help himself, and is not able to keep that slow pace up for very long at all. In no time at all, he is pounding into her from behind, fucking her roughly as he grunts and groans, using her to his heart’s content, with no intention of slowing down until he has filled her up.

“Yes! Oh, big brother, like that!” she screams out, her voice breaking from her lust, and he loves the way that Elise sounds, completely pathetic and entirely his, so needy for him, so broken, and so addicted to his cock that this is the only thing that she wants. “Fuck me harder, use me!”

The Elise he used to know never said such vulgar things, but Corrin finds that he does not miss that at all, shuddering in delight as he understands just how far he can take things with her, without any need to worry about how she might feel, when he knows already that she loves it, that serving and pleasing him has become her new purpose. With all of those thoughts in his mind, it is impossible to contain himself, and he continues pounding into her, fucking her harder and faster with each thrust, pushing himself closer to his limit, until he can’t take it anymore.

Somewhere in the back of his mind, he considers pulling out, but he is too far gone to do such a thing now, and either way, he rather wants to see what happens if he doesn’t pull out, if he never pulls out. Eventually, the truth of his relationship with Elise will come to light like that, but what does any of that matter? He has just been told that his life has been a lie, and that the two of them are not actually related. Who is going to stop him from involving himself with his little sister, from fucking her and knocking her up and keeping her all for his own?

As he fills her with his seed, these thoughts consume him, a power trip like no other, and his confidence is only boosted by the way Elise gives into her own orgasm, convulsing around him as the sensation of her big brother coming inside of her pushes her completely over the edge. They are both left panting after that, struggling to catch their breath, with Elise barely able to stand at all, needing Corrin to hold onto her to make sure that she does not collapse.

Fortunately for her, by the time he has caught his breath, he has decided the next position will not require either of them to stand, and in no time at all, he has Elise pinned to the floor beneath him. She looks up at him with that strange look in her eyes, so devoid of anything that used to make her Elise, but so full of lust and devotion that he does not mind at all. When his head clears, he might have different thoughts about this whole ordeal, but right now, quite full of lust himself, and on one hell of a power trip, the only thing he wants to do is keep fucking her, using her just like she has begged him to, until he has made good on his promise of wearing himself out on her.

All the while, Elise just encourages him, her mind broken beyond repair, and her body belonging only to her big brother.

**Author's Note:**

> If you're interested in my writing updates, please follow my fanfiction twitter @WattStalf


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